Assessment of dietary supplementation with galactomannan oligosaccharides and phytogenics on gut microbiota of European sea bass (Dicentrarchus Labrax) fed low fishmeal and fish oil based diet

Innovative fish diets made of terrestrial plants supplemented with sustainable protein sources free of fish-derived proteins could contribute to reducing the environmental impact of the farmed fish industry. However, such alternative diets may influence fish gut microbial community, health, and, ultimately, growth performance. Here, we developed five fish feed formulas composed of terrestrial plant-based nutrients, in which fish-derived proteins were substituted with sustainable protein sources, including insect larvae, cyanobacteria, yeast, or recycled processed poultry protein. We then analyzed the growth performance of European sea bass (Dicentrarchus labrax L.) and the evolution of gut microbiota of fish fed the five formulations. We showed that replacement of 15% protein of a vegetal formulation by insect or yeast proteins led to a significantly higher fish growth performance and feed intake when compared with the full vegetal formulation, with feed conversion ratio similar to a commercial diet. 16S rRNA gene sequencing monitoring of the sea bass gut microbial community showed a predominance of Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes phyla. The partial replacement of protein source in fish diets was not associated with significant differences on gut microbial richness. Overall, our study highlights the adaptability of European sea bass gut microbiota composition to changes in fish diet and identifies promising alternative protein sources for sustainable aquafeeds with terrestrial vegetal complements.

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Effect of dietary supplementation with Bacillus amyloliquefaciens in the innate immunity in the European sea bass (Dicentrarchus labrax)

Fish & Shellfish Immunology ◽

10.1016/j.fsi.2016.03.079 ◽

2016 ◽

Vol 53 ◽

pp. 70 ◽

Cited By ~ 2

Author(s):

F. Acosta ◽

J. Ramos-Vivas ◽

M. Lazaro-Diez ◽

A. Gonzalez-de Canales ◽

B. Vega ◽

...

Keyword(s):

Innate Immunity ◽

Bacillus Amyloliquefaciens ◽

Dicentrarchus Labrax ◽

Dietary Supplementation ◽

Sea Bass ◽

European Sea Bass

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Effects of fish oil replacement by vegetable oil blend on digestive enzymes and tissue histomorphology of European sea bass (Dicentrarchus labrax) juveniles

Fish Physiology and Biochemistry ◽

10.1007/s10695-015-0130-1 ◽

2015 ◽

Vol 42 (1) ◽

pp. 203-217 ◽

Cited By ~ 29

Author(s):

Carolina Castro ◽

Ana Couto ◽

Amalia Pérez-Jiménez ◽

Cláudia R. Serra ◽

Patricia Díaz-Rosales ◽

...

Keyword(s):

Fish Oil ◽

Vegetable Oil ◽

Digestive Enzymes ◽

Dicentrarchus Labrax ◽

Sea Bass ◽

Fish Oil Replacement ◽

European Sea Bass ◽

Oil Blend

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Dietary Phytogenics and Galactomannan Oligosaccharides in Low Fish Meal and Fish Oil-Based Diets for European Sea Bass (Dicentrarchus labrax) Juveniles: Effects on Gill Structure and Health and Implications on Oxidative Stress Status

Frontiers in Immunology ◽

10.3389/fimmu.2021.663106 ◽

2021 ◽

Vol 12 ◽

Author(s):

Silvia Torrecillas ◽

Genciana Terova ◽

Alex Makol ◽

Antonio Serradell ◽

Victoria Valdenegro-Vega ◽

...

Keyword(s):

Oxidative Stress ◽

Fish Oil ◽

Fish Meal ◽

Raw Materials ◽

Dicentrarchus Labrax ◽

Sea Bass ◽

Control Group ◽

Plant Origin ◽

European Sea Bass ◽

Oxidative Stress Status

An effective replacement for fish meal (FM) and fish oil (FO) based on plant-based raw materials in the feed of marine fish species is necessary for the sustainability of the aquaculture sector. However, the use of plant-based raw materials to replace FM and FO has been associated with several negative health effects, some of which are related to oxidative stress processes that can induce functional and morphological alterations in mucosal tissues. This study aimed to evaluate the effects of dietary oligosaccharides of plant origin (5,000 ppm; galactomannan oligosaccharides, GMOS) and a phytogenic feed additive (200 ppm; garlic oil and labiatae plant extract mixture, PHYTO) on the oxidative stress status and mucosal health of the gills of juvenile European sea bass (Dicentrarchus labrax). The experimental diets, low FM and FO diets (10%FM/6%FO) were supplemented with GMOS from plant origin and PHYTO for 63 days. GMOS and PHYTO did not significantly affect feed utilization, fish growth, and survival. GMOS and PHYTO downregulated the expression of β-act, sod, gpx, cat, and gr in the gills of the fish compared with that in fish fed the control diet. The expression of hsp70 and ocln was upregulated and downregulated, respectively, in the GMOS group compared with that in the control group, whereas the expression of zo-1 was downregulated in the PHYTO group compared with that in the GMOS group. The morphological, histopathological, immunohistochemical, and biochemical parameters of the fish gills were mostly unaffected by GMOS and PHYTO. However, the PHYTO group had lower incidence of lamellar fusion than did the control group after 63 days. Although the tissular distribution of goblet cells was unaffected by GMOS and PHYTO, goblet cell size showed a decreasing trend (−11%) in the GMOS group. GMOS and PHYTO significantly reduced the concentration of PCNA+ in the epithelium of the gills. The above findings indicated that GMOS and PHYTO in low FM/FO-based diets protected the gill epithelia of D. labrax from oxidative stress by modulating the expression of oxidative enzyme-related genes and reducing the density of PCNA+ cells in the gills of the fish.

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Co-culture of Ulva sp. and Dicentrarchus labrax in Recirculating Aquaculture System: effects on growth, retention of nutrients and fatty acid profile

Aquatic Living Resources ◽

10.1051/alr/2020023 ◽

2020 ◽

Vol 33 ◽

pp. 19

Author(s):

Evanthia Chatzoglou ◽

Panorea Kechagia ◽

Aristeidis Tsopelakos ◽

Helen Miliou

Keyword(s):

Fish Oil ◽

Sea Water ◽

Dicentrarchus Labrax ◽

Sea Bass ◽

Recirculating Aquaculture System ◽

Fish Oil Replacement ◽

European Sea Bass ◽

Integrated Aquaculture ◽

Recirculating Aquaculture ◽

Aquaculture System

European sea bass and Ulva sp. were co-cultured in different tanks of an indoor Recirculating Aquaculture System (Ulva-RAS) with bacterial biofilter, in an effort to optimize the efficiency of the system and to further decrease the waste effluent. A system with similar culture conditions, without Ulva, was used as a control-RAS to elucidate integration effects on growth performance and chemical composition of sea bass. The role of Ulva on N and P concentrations, gas (O2, CO2) and pH in water was also investigated. Fish were fed a diet of fish oil replacement (55%) with a mixture of rapeseed oil and palm oil (1:1). Our data showed that Ulva could uptake N and P nutrients, but could also enrich sea water with phosphates. Sea bass reared in Ulva-RAS exhibited isometric growth, while fish in control-RAS showed a positive allometric growth and an increased variance of body weight and length. In addition, sea bass in Ulva-RAS demonstrated significantly higher levels of condition factor (K), feed intake, protein, lipid, P, EPA and DHA content (% wet weight of total body) and lipid productive value, compared to fish in control-RAS. Ulva, after bi-weekly culture, showed increased protein content (60%) compared to wild seaweed collected nearshore. Cultivated Ulva obtained dark green color, doubled chlorophyll concentrations, and exhibited lower levels of saturated and higher levels of certain monounsaturated and n-3 polyunsaturated fatty acids, indicating increased photosynthetic activity. Present results revealed the beneficial effects of Ulva on sea bass growth and quality, which led to an improved response to the nutritional stress imposed by the fish oil replacement with vegetable oils, thus contributing to a sustainable aquaculture. Moreover, it was concluded that Ulva could improve water quality by increasing pH and O2, reducing CO2 and contribute to bioremediation of ammonia and nitrates from water in integrated aquaculture.

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